Abstract: The manufacturing method of high-manganese spheroidal graphite cast iron with exhibiting low magnetism, and excellent wear resistance, castability, and machinability, and having a composition which consists of, 2.5 to 4.0 wt. % of C content, 1.5 to 6.0 wt. % of Si content, 7.0 to 18.0 wt. % of Mn content, and 0.015 to 0.1 wt. % of Mg content, and when the Mn content falls within the range of 7.0 to 10.0 wt. %, consists of 10.0 wt. % or smaller of Ni content, or when the Mn content falls within the range of 10.0 to 18.0 wt. %, consists of Ni content being in the range satisfies the following formula: [Mn wt. %>Ni wt. %], the method comprises heating the above cast iron to the temperature of 1073 to 1373K to decompose the carbides, and then quenching from 1073 to 1273K the resulting cast iron to form a metastable austenite matrix structure that contains no carbide or a reduced amount of carbides.

Abstract: The manufacturing method of high-manganese spheroidal graphite cast iron with exhibiting low magnetism, and excellent wear resistance, castability, and machinability, and having a composition which consists of, 2.5 to 4.0 wt. % of C content, 1.5 to 6.0 wt. % of Si content, 7.0 to 18.0 wt. % of Mn content, and 0.015 to 0.1 wt. % of Mg content, and when the Mn content falls within the range of 7.0 to 10.0 wt. %, consists of 10.0 wt. % or smaller of Ni content, or when the Mn content falls within the range of 10.0 to 18.0 wt. %, consists of Ni content being in the range satisfies the following formula: [Mn wt. %>Ni wt. %], the method comprises heating the above cast iron to the temperature of 1073 to 1373K to decompose the carbides, and then quenching from 1073 to 1273K the resulting cast iron to form a metastable austenite matrix structure that contains no carbide or a reduced amount of carbides.

Abstract: An optical disk apparatus, enabling effective protection from mal functions due to the radio-waves entering inside the apparatus from an outside thereof, comprises a housing 10, a tray 20, which can be inserted/discharged into the housing through an opening portion 12 thereof, a disk motor 50, which is provided in a part of the tray, for driving an optical disk rotationally, an optical pickup 30, which is also provided in a part of the tray, for recording and/or reproducing information with using an optic beam, a signal processing circuit board 40, which is provided in a part of the housing on the other hand, for processing a signal from the optical pickup mounted on the tray, wherein a flexible wiring sheet 100 or 200 is disposed in a part thereof, while being curved, and further an absorbing member 300 or 400 for radio-waves is provided at a position in vicinity of the curved portion 110 or 210, thereby lowering resonances of electromagnetic waves within an inside of the housing, in particular, in the verti

Abstract: A PLL circuit produces a synchronous signal by utilizing a regenerative clock signal in a VFO portion in a regenerative signal which was read out from a recording medium in sections. When a defective portion is present in a regenerative clock signal, the same sector is read out again from the recording medium to obtain the regenerative signal. A loop gain of the PLL circuit is made to be low in the defective portion of the regenerative signal which was read out again, thereby to prevent the synchronous fault of the PLL circuit due to the defective portion.

Abstract: A method of welding studs inclusive of a bolt or the like to an underwater structure or a land structure in the rain or for mounting anticorrosive members, wherein the tip of the stud held by the welding gun is enclosed by a resilient, heat-resisting water sealing member and a gas generating agent is applied to the tip of the stud. The water sealing member is brought in contact with a base metal and an arc is generated by a current across the stud and the base metal so that the arc heat causes gas to be generated from the gas generating agent to force any water around the stud tip out of the water sealing member under a gas pressure, and then the stud is welded to the base metal in the absence of water.